PDPN and breast cancer: For example, neutrophils can promote lung metastasis of breast cancer by secreting leukotriene B4 (Wculek and Malanchi, 2015), whereas podoplanin-expressing macrophages can contribute to the lymphoinvasion of breast cancer cells by binding with lymphatic endothelial cells to trigger matrix remodeling and lymphangiogenesis (Bieniasz-Krzywiec et al., 2019).